Insulation Question

tmix · Post by **tmix** » Mon Apr 03, 2006 1:09 am

I am almost afraid to ask this question, but I must.

I ordered a lot of insulation from Lowes for the walls and ceilings of my new building. When they arrived (on pallets shrink wrapped) I never really looked at them much. I was moving around some wood to get to other supplies and noticed the wall insulation was described on the packaging as "totally encapsulated" batts.

ouch....

I wonder now if that means that the batts have plastic wrapped all the way around, and if so, is that really an issue?

I am installing the stuff in single sided,double walled rooms with a 2 to 3.5 inch airgap between walls.
Does the plastic hurt anything acoustically?

I have had this stuff for 4 months so I dont think I can return it without a lot of hassle.

Tom

Sandersd · Post by **Sandersd** » Mon Apr 03, 2006 1:35 am

Some will say it creates a "third leaf". My belief is in the world of theoretical acoustics, yea maybe, but realistically, you'll never hear a difference.

If it concerns you just remove the plastic. I have the same insulation in my attic and can attest it's not difficult to remove.

SonicClang · Post by **SonicClang** » Mon Apr 03, 2006 1:39 am

Ouch is right... You really don't want a face on the insulation, not paper or plastic. It prevents high frequencies from entering the insulation and thus being absorbed by it, negating its usefulness. If you haven't opened it up see if you can exchange it. They might be open to it. Also look to see if it's EXACTLY what you ordered. If it's not just throw a fit until they exchange it.

But like Sandersd said, realistically you probably won't notice a difference.

tmix · Post by **tmix** » Mon Apr 03, 2006 2:50 am

That is my thought as well.
Probably wont notice a difference.

I may just pull the face off once I get it up.

Tom

SonicClang · Post by **SonicClang** » Mon Apr 03, 2006 3:11 am

I've accidentally bought paper-faced insulation before and just to be safe I pull the paper off. It's easy enough to do.

rod gervais · Post by **rod gervais** » Mon Apr 03, 2006 3:41 am

OK,

Everyone back up for a moment.

This can not hurt the room acoustically - because we aren't talking treatments here - but rather insulation.

There is an innner and an outer face - the inner face is a vapor retarder - the outer face is vapor retarder but has perferations to allow the insulation to breathe in the wall cavity.

UNless you plan to throw away a bunch of money and time(you will still need a vapor barrier - so if you remove this you need to add poly) then I would suggest that you leave it as is.

If it does in fact decrease the amount of HF passing through it - then you just (slightly) increased your TL value of the wall.

Rod

rod gervais · Post by **rod gervais** » Mon Apr 03, 2006 3:43 am

Sandersd wrote:Some will say it creates a "third leaf". My belief is in the world of theoretical acoustics, yea maybe, but realistically, you'll never hear a difference.

Sandersd,

Some might indeed say that - but then some would be wrong........

Rod

tmix · Post by **tmix** » Mon Apr 03, 2006 9:54 pm

Rod
Thanks for the input.
I was hoping the barrier WAS perforated.
I do want to leave it and not have to put additional barrier material.

Tom